Service Function Chaining (SFC) facilitates the creation of composite (network) services that can include an ordered set of Service Functions (SF) that are applied to packets and/or frames and/or flows selected as a result of classification. One desired advantage of SFC is to be able to classify a packet once, and apply the resulting policy across each SF node forming the SFC. To achieve this desired result, the resulting policies from classification can be carried in packet metadata.
In Services Function Chaining (SFC), a packet may traverse different devices or nodes for the same or multiple vendors, including off-path devices, such as statistics collectors. Carrying policies in metadata may not be sufficient for every node in the SFC to understand the policies, nor guarantee interoperability across different devices.